HOMOLEPTIC YTTRIUM AND LANTHANIDE COMPLEXES OF AMINOTROPONIMINATES AND AMINOTROPONATES - EXPERIMENTAL AND THEORETICAL-STUDIES

Density functional theory (DFT) calculations were performed for the ho moleptic aminotroponiminate complexes [Ln {C7H5(NPri)(2)}(3)] (Ln = Y or Sm) in order to get structural and energetic information about the possible isomers. The calculations predict a propeller-shaped chiral i somer of D-3, symmetry as lowest in energy. Two less stable isomers tu rned out to be stationary points of higher order. One is likely to be close to a structure acting as intermediate in the mechanism of rapid racemisation observed by NMR studies. Based on these results experimen tal and DFT computational studies of homoleptic lanthanide complexes w ith the new ligand system aminotroponate C7H5(NPri)O- were carried out . This related but asymmetric ligand results in a slower isomerisation and thus detection of the concerned species: H-1 NMR experiments show ed an equilibrium of several [Y{C7H5(NPri)O}(3)] isomers in solution, in agreement with the computational results.